1. Field of the Invention
The present invention relates to a portable terminal device, and more particularly, to an invention preferable for a portable terminal device enabling a TV broadcast to be watched.
2. Description of the Related Art
Cellular phones include one that has an antenna for receiving a TV broadcast wave transmitted from a broadcast base station; display a TV image on a display screen on the basis of the TV broadcast wave; and output TV voice corresponding to the TV image to thereby enable a TV broadcast to be watched.
As an example of this sort of cellular phone, there is one adapted such that a display screen is formed in a rectangular shape, and the display screen can be switched between a vertically long display state and a horizontally long display state. The cellular phone of which the display screen is formed in a rectangular shape as described is adapted such that, for example, in the above-described vertically long display state, a TV image is displayed with a longer direction of the display screen being vertical, whereas in the above-described horizontally long display state, the TV image is displayed with a shorter direction of the display screen being vertical.
Meanwhile, a TV image based on a TV broadcast wave transmitted from a broadcast base station may include characters and the like. For example, in a relay broadcast of a sport such as baseball, football, or volleyball, scores are typically displayed at the end of a display screen. However, a display screen of a cellular phone is very small as compared with that of a typical home-use TV set, and therefore the score display may be difficult to recognize.
For this reason, there is proposed a technique in which if characters and the like displayed on a display screen of a cellular phone are difficult to visually recognize, a corresponding part is enlarged and displayed (see, for example, Patent document 1 or 2).
In the cellular phone disclosed in Patent document 1 or 2, an entire area of the display screen is equally sectioned corresponding to an arrangement of respective keys in a ten-key pad to form enlargement target areas. Also, the cellular phone is adapted such that if a key operation is performed with a predetermined key, an image within an enlargement target area corresponding to the key is enlarged and displayed.
In addition, the cellular phone having the enlargement display function in Patent document is adapted to, by performing a long pressing operation of the predetermined key for a predetermined time period, enlarge and display the image within the enlargement target area corresponding to the key. Also, the cellular phone is adapted such that when the enlarged image display state is restored to an original image state, the same key is again operated.
Also, in Patent document 2, a system is adapted such that operations of dividing an image into a plurality of pieces to form divided images, and enlarging the divided images at a predetermined magnification are performed in a server, and data on the enlarged images created in the server in this manner is transmitted to the cellular phone.    Patent document 1: Japanese Unexamined Patent Publication No. 2005-316558    Patent document 2: Japanese Unexamined Patent Publication No. 2003-273971